In accordance with an aspect of the exemplary embodiments, the embodiments relate to an electrical junction box to be mounted on a motor vehicle or the like and more particularly relates to an electrical junction box to be fitted into an attachment hole in a vehicle body panel to be mounted on a vehicle body.
Electrical equipment in a motor vehicle is generally contained within a box such as a fuse box, a junction box, or a connector holder. The electrical junction box is generally attached to a vehicle body panel in a vehicle room or an engine room. There is an electrical junction box in which a protruding amount into the vehicle room or the like is reduced by merely fitting the box into an attachment hole in the vehicle body panel when the box is mounted on the vehicle body panel.
Such electrical junction box has been disclosed in JP HEI 11(1999)-238557 A (Patent Document 1). The electrical junction box is generally provided with an engagement fixing section to be secured to an opening peripheral edge section around the attachment hole in the vehicle body panel. The electrical junction box can be secured to the vehicle body panel by merely fitting the engagement fixing section into the attachment hole. Such engagement fixing section includes a flange portion to be superimposed on a front side surface on a whole opening peripheral edge section around the attachment hole in the vehicle body panel, and a plurality of engagement pawls to be locked on a rear side surface on the opening peripheral edge section around the attachment hole in the vehicle body panel. When the electrical junction box is fitted into the attachment hole, the engagement pawls are elastically deformed to turn to the rear side of the vehicle body panel and the vehicle body panel is clamped between the engagement pawls and the flange portion. As a result, the electrical junction box is secured to the vehicle body panel.
When the electrical junction box is fitted into the attachment hole in the vehicle body panel, clearance should be left between the opening peripheral edge section around the attachment hole and the electrical junction box. Such clearance can be used to pass a cable through the vehicle body panel so as to arrange the cable in the vehicle body or it can be used as a service hole for maintenance.
However, in an attachment structure of the conventional electrical junction box as disclosed in Patent Document 1, there is a problem that it is difficult to provide a large clearance between an outer peripheral surface of the electrical junction box and the opening peripheral edge section around the attachment hole. That is, in order to form a large clearance, not only the flange portion to be provided on the outer peripheral surface of the electrical junction box must be extended greatly on the outer peripheral surface, but also the flange portion must be separated on the outer peripheral surface. This will cause a problem that strength of the flange portion itself and fixing strength of the flange portion onto the vehicle body panel are greatly reduced.
In addition, in the attachment structure of the electrical junction box disclosed in Patent Document 1, when the electrical junction box is removed from the vehicle body panel after mounting, there is a problem that it is difficult to release engagement pawls from a rear side surface of the vehicle body panel. That is, in order to release the engagement pawls from a front side of the vehicle body panel, it is generally necessary to provide the flange portion with a working hole for passing a tool such as a lever. This will cause a problem that a mold for the electrical junction box becomes complicated and a releasing work is troublesome since the tool must be inserted into a small hole to release the engagement pawls.